Combining Texts

All the ideas for 'works', 'Intro to 2nd ed of Principia Mathematica' and 'Chapters on Scepticism'

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3 ideas

6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz]
     Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points.
     From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13
     A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry.
7. Existence / C. Structure of Existence / 6. Fundamentals / d. Logical atoms
Given all true atomic propositions, in theory every other truth can thereby be deduced [Russell]
     Full Idea: Given all true atomic propositions, together with the fact that they are all, every other true proposition can theoretically be deduced by logical methods.
     From: Bertrand Russell (Intro to 2nd ed of Principia Mathematica [1925], p.xv)
     A reaction: This is evidently his strongest statement of the ideal underlying logical atomism. The atoms were initially sense-date, but then became atomic propositions saying an object has a property.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds
If we can't know minds, we can't know if Pyrrho was a sceptic [Theodosius, by Diog. Laertius]
     Full Idea: We can't say the school of Pyrrho is sceptical, because the motion of the mind in each individual is incomprehensible to others, so we don't know Pyrrho's disposition.
     From: report of Theodosius (Chapters on Scepticism [c.100 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.8